/*
 * this is an efficient C replacement for the find_cat.bac, the main source of
 * slowness in PPM. in my non-scientific tests, it processes the entire Trisquel
 * package database in 1.5 seconds, while find_cat.bac needs 1 second for each
 * of the 40,000 packages in the database.
 *
 * to build:
 * musl-gcc -static -O3 -fomit-frame-pointer -ffunction-sections -fdata-sections -fmerge-all-constants -Wl,--sort-common -Wl,-gc-sections -o find_cat find_cat.c
 * strip --strip-all -R .note -R .comment find_cat
 *
 * cheers,
 * iguleder, October 2015
 */

#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <ctype.h>

#define BUF_SIZE (32 * 1024)
#define MAX_PKGS (60000)
#define MAX_CATS (128)
#define NAME_SIZE (64)
#define DESC_SIZE (512)
#define MAX_KWDS (512)

static const unsigned long crc32_table[256] = {
	0x00000000, 0x77073096, 0xEE0E612C, 0x990951BA, 0x076DC419, 0x706AF48F,
	0xE963A535, 0x9E6495A3, 0x0EDB8832, 0x79DCB8A4, 0xE0D5E91E, 0x97D2D988,
	0x09B64C2B, 0x7EB17CBD, 0xE7B82D07, 0x90BF1D91, 0x1DB71064, 0x6AB020F2,
	0xF3B97148, 0x84BE41DE, 0x1ADAD47D, 0x6DDDE4EB, 0xF4D4B551, 0x83D385C7,
	0x136C9856, 0x646BA8C0, 0xFD62F97A, 0x8A65C9EC, 0x14015C4F, 0x63066CD9,
	0xFA0F3D63, 0x8D080DF5, 0x3B6E20C8, 0x4C69105E, 0xD56041E4, 0xA2677172,
	0x3C03E4D1, 0x4B04D447, 0xD20D85FD, 0xA50AB56B, 0x35B5A8FA, 0x42B2986C,
	0xDBBBC9D6, 0xACBCF940, 0x32D86CE3, 0x45DF5C75, 0xDCD60DCF, 0xABD13D59,
	0x26D930AC, 0x51DE003A, 0xC8D75180, 0xBFD06116, 0x21B4F4B5, 0x56B3C423,
	0xCFBA9599, 0xB8BDA50F, 0x2802B89E, 0x5F058808, 0xC60CD9B2, 0xB10BE924,
	0x2F6F7C87, 0x58684C11, 0xC1611DAB, 0xB6662D3D, 0x76DC4190, 0x01DB7106,
	0x98D220BC, 0xEFD5102A, 0x71B18589, 0x06B6B51F, 0x9FBFE4A5, 0xE8B8D433,
	0x7807C9A2, 0x0F00F934, 0x9609A88E, 0xE10E9818, 0x7F6A0DBB, 0x086D3D2D,
	0x91646C97, 0xE6635C01, 0x6B6B51F4, 0x1C6C6162, 0x856530D8, 0xF262004E,
	0x6C0695ED, 0x1B01A57B, 0x8208F4C1, 0xF50FC457, 0x65B0D9C6, 0x12B7E950,
	0x8BBEB8EA, 0xFCB9887C, 0x62DD1DDF, 0x15DA2D49, 0x8CD37CF3, 0xFBD44C65,
	0x4DB26158, 0x3AB551CE, 0xA3BC0074, 0xD4BB30E2, 0x4ADFA541, 0x3DD895D7,
	0xA4D1C46D, 0xD3D6F4FB, 0x4369E96A, 0x346ED9FC, 0xAD678846, 0xDA60B8D0,
	0x44042D73, 0x33031DE5, 0xAA0A4C5F, 0xDD0D7CC9, 0x5005713C, 0x270241AA,
	0xBE0B1010, 0xC90C2086, 0x5768B525, 0x206F85B3, 0xB966D409, 0xCE61E49F,
	0x5EDEF90E, 0x29D9C998, 0xB0D09822, 0xC7D7A8B4, 0x59B33D17, 0x2EB40D81,
	0xB7BD5C3B, 0xC0BA6CAD, 0xEDB88320, 0x9ABFB3B6, 0x03B6E20C, 0x74B1D29A,
	0xEAD54739, 0x9DD277AF, 0x04DB2615, 0x73DC1683, 0xE3630B12, 0x94643B84,
	0x0D6D6A3E, 0x7A6A5AA8, 0xE40ECF0B, 0x9309FF9D, 0x0A00AE27, 0x7D079EB1,
	0xF00F9344, 0x8708A3D2, 0x1E01F268, 0x6906C2FE, 0xF762575D, 0x806567CB,
	0x196C3671, 0x6E6B06E7, 0xFED41B76, 0x89D32BE0, 0x10DA7A5A, 0x67DD4ACC,
	0xF9B9DF6F, 0x8EBEEFF9, 0x17B7BE43, 0x60B08ED5, 0xD6D6A3E8, 0xA1D1937E,
	0x38D8C2C4, 0x4FDFF252, 0xD1BB67F1, 0xA6BC5767, 0x3FB506DD, 0x48B2364B,
	0xD80D2BDA, 0xAF0A1B4C, 0x36034AF6, 0x41047A60, 0xDF60EFC3, 0xA867DF55,
	0x316E8EEF, 0x4669BE79, 0xCB61B38C, 0xBC66831A, 0x256FD2A0, 0x5268E236,
	0xCC0C7795, 0xBB0B4703, 0x220216B9, 0x5505262F, 0xC5BA3BBE, 0xB2BD0B28,
	0x2BB45A92, 0x5CB36A04, 0xC2D7FFA7, 0xB5D0CF31, 0x2CD99E8B, 0x5BDEAE1D,
	0x9B64C2B0, 0xEC63F226, 0x756AA39C, 0x026D930A, 0x9C0906A9, 0xEB0E363F,
	0x72076785, 0x05005713, 0x95BF4A82, 0xE2B87A14, 0x7BB12BAE, 0x0CB61B38,
	0x92D28E9B, 0xE5D5BE0D, 0x7CDCEFB7, 0x0BDBDF21, 0x86D3D2D4, 0xF1D4E242,
	0x68DDB3F8, 0x1FDA836E, 0x81BE16CD, 0xF6B9265B, 0x6FB077E1, 0x18B74777,
	0x88085AE6, 0xFF0F6A70, 0x66063BCA, 0x11010B5C, 0x8F659EFF, 0xF862AE69,
	0x616BFFD3, 0x166CCF45, 0xA00AE278, 0xD70DD2EE, 0x4E048354, 0x3903B3C2,
	0xA7672661, 0xD06016F7, 0x4969474D, 0x3E6E77DB, 0xAED16A4A, 0xD9D65ADC,
	0x40DF0B66, 0x37D83BF0, 0xA9BCAE53, 0xDEBB9EC5, 0x47B2CF7F, 0x30B5FFE9,
	0xBDBDF21C, 0xCABAC28A, 0x53B39330, 0x24B4A3A6, 0xBAD03605, 0xCDD70693,
	0x54DE5729, 0x23D967BF, 0xB3667A2E, 0xC4614AB8, 0x5D681B02, 0x2A6F2B94,
	0xB40BBE37, 0xC30C8EA1, 0x5A05DF1B, 0x2D02EF8D
};

/* based on CRC-32 version 2.0.0 by Craig Bruce, 2006-04-29, public domain -
 * http://csbruce.com/software/crc32.c */
static unsigned long crc32(const unsigned long in,
                           const unsigned char *buf,
                           const size_t len)
{
	size_t i;
	unsigned long crc32;

	crc32 = in ^ 0xFFFFFFFF;
	for (i = 0; len > i; ++i)
		crc32 = (crc32 >> 8) ^ crc32_table[(crc32 ^ buf[i]) & 0xFF];

	return crc32 ^ 0xFFFFFFFF;
}

int main(int argc, char *argv[])
{
	char desc[DESC_SIZE];
	char *namecats[MAX_CATS], *kwdcats[MAX_CATS];
	unsigned long *pkgs[MAX_CATS];
	char **kwds[MAX_CATS];
	int npkgs[MAX_CATS], nkwds[MAX_CATS];
	char *fields[12];
	char name[NAME_SIZE];
	unsigned long initcrc, crc;
	FILE *infp, *catf;
	char *buf, *pos, *nextpos, *iobuf;
	int nnamecats, nkwdcats, i, j, len, isdeb;

	iobuf = malloc(BUF_SIZE);

	if (argc == 1)
		infp = stdin;
	else
		infp = fopen(argv[1], "r");
	setbuffer(infp, iobuf, BUF_SIZE);

	buf = malloc(BUF_SIZE);
	catf = fopen("/usr/local/petget/categories.dat", "r");
	if (NULL == catf) goto bail;

	initcrc = crc32(0, NULL, 0);

	nnamecats = nkwdcats = 0;
	while (NULL != fgets(buf, BUF_SIZE, catf)) {
		/* hash the names of the packages in each category */
		if ('P' == buf[0]) {
			pos = strchr(buf, '=');
			if (('"' == pos[1]) && ('"' == pos[2])) continue;
			pos[0] = '\0';
			pos += 3;

			pkgs[nnamecats] = malloc(sizeof(unsigned long) * MAX_PKGS);
			len = strlen(buf + 7);
			namecats[nnamecats] = strndup(buf + 7, len);
			for (i = 0; len > i; ++i) if ('_' == namecats[nnamecats][i]) namecats[nnamecats][i] = ';';
			npkgs[nnamecats] = 0;

			do {
				nextpos = strchr(pos, ' ');
				nextpos[0] = '\0';

				pkgs[nnamecats][npkgs[nnamecats]] = crc32(initcrc, (unsigned char *) pos, nextpos - pos);

				++npkgs[nnamecats];
				if ('"' == nextpos[1]) break;
				pos = nextpos + 1;
			} while (1);

			++nnamecats;
		/* list the keywords in each category */
		} else if ('K' == buf[0]) {
			pos = strchr(buf, '=');
			pos[0] = '\0';
			pos += 3;

			kwds[nkwdcats] = malloc(sizeof(char *) * MAX_KWDS);
			len = strlen(buf + 7);
			kwdcats[nkwdcats] = strndup(buf + 7, len);
			for (i = 0; len > i; ++i) if ('_' == kwdcats[nkwdcats][i]) kwdcats[nkwdcats][i] = ';';
			nkwds[nkwdcats] = 0;

			do {
				nextpos = strchr(pos, ' ');
				nextpos[0] = '\0';
				len = nextpos - pos;
				kwds[nkwdcats][nkwds[nkwdcats]] = malloc(len + 1);
				/* replace underscores with spaces - that's how categories.dat
				 * specifies keywords with spaces */
				for (i = 0; len > i; ++i) if ('_' == pos[i]) pos[i] = ' ';
				memcpy(kwds[nkwdcats][nkwds[nkwdcats]], pos, len + 1);

				++nkwds[nkwdcats];
				if ('"' == nextpos[1]) break;
				pos = nextpos + 1;
			} while (1);

			++nkwdcats;
		}
	}

	while (NULL != fgets(buf, BUF_SIZE, infp)) {
		pos = buf;
		fields[0] = pos;
		for (i = 1; 12 > i; ++i) {
			pos = strchr(pos, '|');
			if (NULL == pos) break;
			pos[0] = '\0';
			++pos;
			fields[i] = pos;
		}

		if ((0 == strcmp(fields[10], "ubuntu")) ||
		    (0 == strcmp(fields[10], "trisquel")) ||
		    (0 == strcmp(fields[10], "debian")) ||
		    (0 == strcmp(fields[10], "devuan")) ||
		    (0 == strcmp(fields[10], "raspbian"))) {
			pos = strrchr(fields[5], '/');
			if (NULL == pos)
				strcpy(name, fields[6]);
			else
				strcpy(name, pos + 1);
			isdeb = 1;
		} else {
			strcpy(name, fields[1]);
			isdeb = 0;
		}

		/* convert the package name to lowercase */
		len = strlen(name);
		for (j = 0; len > j; ++j) name[j] = tolower(name[j]);

		/* libraries are always in the BuildingBlock section */
		if (0 == strncmp(name, "lib", 3)) {
			fields[4] = "BuildingBlock";
			goto print;
		}

		/* then, check if the package belongs to a category by name - we compare
		 * hashes, so it's not that slow */
		crc = crc32(initcrc, (unsigned char *) name, len);
		for (i = 0; nnamecats > i; ++i) {
			for (j = 0; npkgs[i] > j; ++j) {
				if (crc == pkgs[i][j]) {
					fields[4] = namecats[i];
					goto print;
				}
			}
		}

		strcpy(desc, fields[9]);
		for (j = 0; strlen(desc) > j; ++j) desc[j] = tolower(desc[j]);

		/* check if the package belongs to a category by description keyword */
		for (i = 0; nkwdcats > i; ++i) {
			for (j = 0; nkwds[i] > j; ++j) {
				if (NULL != strstr(desc, kwds[i][j])) {
					fields[4] = kwdcats[i];
					goto print;
				}
			}
		}

		/* finally, as fallback, try the most naive method first - look for
		 * known categories */
		if (isdeb) {
			len = strlen(fields[4]);
			if (len >= 3) {
				if (0 == strncmp(fields[4] + len - 3, "vcs", 3)) {
					fields[4] = "Utility;development";
					goto print;
				} else if (0 == strncmp(fields[4] + len - 3, "doc", 3)) {
					fields[4] = "Help";
					goto print;
				} else if (len >= 5) {
					if (0 == strncmp(fields[4] + len - 5, "admin", 5)) {
						fields[4] = "Setup";
						goto print;
					} else if (0 == strncmp(fields[4] + len - 5, "games", 5)) {
						fields[4] = "Fun";
						goto print;
					} else if (len >= 7) {
						if (0 == strncmp(fields[4] + len - 7, "science", 7)) {
							fields[4] = "Fun";
							goto print;
						}
					}
				}
			}
		}
		fields[4] = "BuildingBlock";

print:
		for (i = 0; 11 > i; ++i) {
			fputs(fields[i], stdout);
			putc('|', stdout);
		}
		fputs(fields[11], stdout);
	}

	for (--nkwdcats; 0 <= nkwdcats; --nkwdcats) {
		for (i = 0; nkwds[nkwdcats] > i; ++i) free(kwds[nkwdcats][i]);
		free(kwds[nkwdcats]);
		free(kwdcats[nkwdcats]);
	}
	for (--nnamecats; 0 <= nnamecats; --nnamecats) {
		free(pkgs[nnamecats]);
		free(namecats[nnamecats]);
	}

	fclose(catf);

bail:
	free(buf);
	if (argc != 1) fclose(infp);
	free(iobuf);

	return EXIT_SUCCESS;
}
